Method for producing a stacked photovoltaic device

Abstract

A stacked photovoltaic device which includes a first photovoltaic unit having an amorphous silicon layer 8 as a photoelectric conversion layer, and a second photovoltaic unit having a microcrystalline silicon layer 5 as a photoelectric conversion layer and succeeding backwardly from the first photovoltaic unit closer to a light incidence plane. The microcrystalline silicon layer 5 serving as the photoelectric conversion layer in the second photovoltaic unit has a ratio α 2 (═I(Si—O)/I(Si—H)) greater than a ratio α 1 (═I(Si—O)/I(Si—H)) of the amorphous silicon layer 8 serving as the photoelectric conversion layer in the first photovoltaic unit, where I(Si—O) is a peak area for the Si—O stretching mode of each silicon layer and I(Si—H) is a peak area for the Si—H stretching mode of each silicon layer when the amorphous and microcrystalline silicon layers 8 and 5 are measured by infrared absorption spectroscopy. Also, a short-circuit current Isc 2 of the second photovoltaic unit is greater than a short-circuit current Isc 1 of the first photovoltaic unit.

1 .- 3 . (canceled) 
     
     
         4 . A method for producing a stacked photovoltaic device which includes a first photovoltaic unit and a second photovoltaic unit succeeding backwardly from the first photovoltaic unit closer to a light incidence plane, said first photovoltaic unit having a multilayer structure comprising a one conductive type non-single-crystalline semiconductor layer, an amorphous silicon layer which is substantially intrinsic and serves as a photoelectric conversion layer contributing to power generation and another conductive type non-single-crystalline semiconductor layer, said second photovoltaic unit having a multilayer structure comprising a one conductive type microcrystalline semiconductor layer, a microcrystalline silicon layer which is substantially intrinsic and serves as a photoelectric conversion layer contributing to power generation and another conductive type microcrystalline semiconductor layer;
 wherein the microcrystalline silicon layer as the photoelectric conversion layer in the second photovoltaic unit is formed by controlling a reaction pressure, without adding a gas containing oxygen to a reaction gas, so as to have a ratio α 2  (═I(Si—O)/I(Si—H)) greater than a ratio α 1  (═I(Si—O)/I(Si—H)) of said amorphous silicon layer as the photoelectric conversion layer in the first photovoltaic unit, where I(Si—O) is a peak area for the Si—O stretching mode of each silicon layer and I(Si—H) is a peak area for the Si—H stretching mode of each silicon layer, when measured by infrared absorption spectroscopy.   
     
     
         5 . The method for producing a stacked photovoltaic device as recited in  claim 4 , wherein each of said non-single-crystalline semiconductor layers is a non-single-crystalline silicon layer or a non-single-crystalline silicon alloy layer. 
     
     
         6 . The method for producing a stacked photovoltaic device as recited in  claim 4 , wherein a short-circuit current Isc 2  of the second photovoltaic unit is greater than a short-circuit current Isc 1  of the first photovoltaic unit.